A snake that bites its own tail. Acquisition and loss of concepts in children and semantic dementia patients through the analysis of drawings.

Objective: The structure of the semantic network is constructed and organized during childhood development. Previous publications have hypothesized that neurodegenerative diseases would lead to a disruption of this network reversing the steps acquired in childhood. Semantic Dementia (SD) is a subtype of frontotemporal lobe degeneration in which the main symptom is a specific loss of semantic memory.

Cognitive and Behavioral Profiles of Left and Right Semantic Dementia: Differential Diagnosis with Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease.

Background: Semantic dementia (SD) is a subtype of frontotemporal dementia (FTD) characterized by semantic memory loss and preserved abilities of other cognitive functions. The clinical manifestations of SD require a differential diagnosis with Alzheimer's disease (AD), especially those with early onset, and behavioral variant FTD (bvFTD).

Objective: The present study aimed to compare cognitive performances and neuropsychiatric symptoms in a population of AD, bvFTD, and left and right SD defined with the support of molecular imaging (amyloid and 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography) and assessed the accuracy of different neuropsychological markers in distinguishing these neurodegenerative diseases.

A Brief Drawing Task for the Differential Diagnosis of Semantic Dementia.

Background: Semantic dementia (SD) is a subtype of frontotemporal lobe degeneration characterized by semantic loss, with other cognitive functions initially preserved. SD requires differential diagnosis with Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD). Semantic knowledge can be evaluated through different tests; however, most of them depend on language.

Persistent isolated mydriasis as an early sign of internal carotid artery dissection: Pourfour du petit syndrome.

Background: The dissection of the internal carotid artery (ICA) is commonly associated with miosis in Bernard-Horner syndrome (BHS). The presence of mydriasis is exceptional but can occur in the context of Pourfour du Petit syndrome (PDPS), a rare entity opposite of BHS accompanied by eyelid retraction and hyperhidrosis and caused by hyperactivity of the sympathetic cervical chain.

Aim: To report on a case of PDPS as the first manifestation of an ICA dissection.

Utility of Amyloid and FDG-PET in Clinical Practice: Differences Between Secondary and Tertiary Care Memory Units.

The clinical utility of amyloid positron emission tomography (PET) has not been fully established. Our aim was to evaluate the effect of amyloid imaging on clinical decision making in a secondary care unit and compare our results with a previous study in a tertiary center following the same methods. We reviewed retrospectively 151 cognitively impaired patients who underwent amyloid (Pittsburgh compound B [PiB]) PET and were evaluated clinically before and after the scan in a secondary care unit.

Cerebral changes and disrupted gray matter cortical networks in asymptomatic older adults at risk for Alzheimer's disease.

The diagnostic value of cerebrospinal fluid (CSF) biomarkers is well established in Alzheimer's disease, but our current knowledge about how abnormal CSF levels affect cerebral integrity, at local and network levels, is incomplete in asymptomatic older adults. Here, we have collected CSF samples and performed structural magnetic resonance imaging scans in cognitively normal elderly as part of a cross-sectional multicenter study (SIGNAL project). To identify group differences in cortical thickness, white matter volume, and properties of structural networks, participants were split into controls (N = 20), positive amyloid-β (Aβ) (N = 19), and positive phosphorylated tau (N = 18).

MicroRNA Profile in Patients with Alzheimer's Disease: Analysis of miR-9-5p and miR-598 in Raw and Exosome Enriched Cerebrospinal Fluid Samples.

Background: MicroRNAs have been postulated as potential biomarkers for Alzheimer's disease (AD). Exosomes are nanovesicles which transport microRNAs, proteins, and other cargos. It has been hypothesized that the exosome traffic might be increased in neurodegenerative disorders.

MAPT H1 Haplotype is Associated with Late-Onset Alzheimer's Disease Risk in APOEɛ4 Noncarriers: Results from the Dementia Genetics Spanish Consortium.

The MAPT H1 haplotype has been linked to several disorders, but its relationship with Alzheimer's disease (AD) remains controversial. A rare variant in MAPT (p.A152T) has been linked with frontotemporal dementia (FTD) and AD.

Amyloid precursor protein metabolism and inflammation markers in preclinical Alzheimer disease.

Objective: To investigate CSF markers involved in amyloid precursor protein processing, neuronal damage, and neuroinflammation in the preclinical stages of Alzheimer disease (AD) and participants with suspected non-Alzheimer pathology (SNAP).

Methods: We collected CSF from 266 cognitively normal volunteers participating in a cross-sectional multicenter study (the SIGNAL study) to investigate markers involved in amyloid precursor protein processing (Aβ42, sAPPβ, β-secretase activity), neuronal damage (total-tau [t-tau], phospho-tau [p-tau]), and neuroinflammation (YKL-40). We analyzed the relationship among biomarkers, clinical variables, and the APOE genotype, and compared biomarker levels across the preclinical stages of the National Institute on Aging-Alzheimer's Association classification: stage 0, 1, 2, 3, and SNAP.

Epistasis between intracellular cholesterol trafficking-related genes (NPC1 and ABCA1) and Alzheimer's disease risk.

Aberrant cholesterol metabolism has been implicated in Alzheimer's disease (AD). Recent findings have suggested an interaction of Niemann-Pick C1 (NPC1) and ATP-binding cassette transporter A1 (ABCA1) proteins in intracellular cholesterol transport and in maintaining cell cholesterol balance. Underexpression of NPC1 in concert with under-expression of ABCA1 would result in increased cholesterol accumulation and increased AD risk.

DYRK1A genetic variants are not linked to Alzheimer's disease in a Spanish case-control cohort.

Background: As dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) has been implicated in the abnormal hyperphosphorylation of tau in Alzheimer's disease (AD) brain, and the development of neurofibrillary tangles, we examined the contribution of this gene to the susceptibility for AD.

Methods: We examined genetic variations of DYRK1A by genotyping haplotype tagging SNPs (htSNPs) (rs11701483, rs2835740, rs1137600, rs2835761, rs2835762, rs2154545 and rs8132976) in a group of 634 Spanish AD cases and 733 controls.

Results: There were no differences in the genotypic, allelic or haplotypic distributions between cases and controls in the overall analysis or after stratification by APOE epsilon4 allele.

APOE dependent-association of PPAR-γ genetic variants with Alzheimer's disease risk.

The peroxisome proliferator-activated receptor-γ (PPAR-γ) is a ligand-inducible transcription factor that suppresses microglial inflammatory responses and inhibits amyloid beta (Aβ) production through promoting cholesterol efflux from glial cells. PPAR-γ agonists have been advanced as a new disease altering approach to Alzheimer's disease (AD), with rosiglitazone therapy having improved cognition in those AD patients that did not possess an Apolipoprotein E (APOE) ε4 allele. The current study was designed to explore the effect of interactions between PPAR-γ and APOE gene polymorphisms on the AD risk.

No association of CDK5 genetic variants with Alzheimer's disease risk.

Background: As cyclin-dependent kinase 5 (CDK5) has been implicated in the abnormal hyperphosphorylation of tau in Alzheimer's disease (AD) brain, and the development of neurofibrillary tangles, we examined the contribution of this gene to the susceptibility for AD.

Methods: We examined genetic variations of CDK5 by genotyping haplotype tagging SNPs (htSNPs) (rs9278, rs2069459, rs891507, rs2069454, rs1549759 and rs2069442) in a group of 408 Spanish AD cases and 444 controls.

Results: There were no differences in the genotypic, allelic or haplotypic distributions between cases and controls in the overall analysis or after stratification by APOE epsilon4 allele.

Interaction between HMGCR and ABCA1 cholesterol-related genes modulates Alzheimer's disease risk.

A number of studies suggest that increased cellular cholesterol levels induce high amyloid beta (Abeta) production, which is central to the pathogenesis of Alzheimer's disease (AD). In the brain, glial cells have hydroxy-methylglutaryl-coenzyme A reductase (HMGCR) as the major rate-limiting enzyme in the novo synthesis of cholesterol, which once synthesized, is secreted via the cholesterol transporter ABCA1. Overexpression of HMGCR in concert with underexpression of ABCA1 would result in increased cholesterol accumulation, induction of Abeta production, and increased AD risk.

Synergistic effect of heme oxygenase-1 and tau genetic variants on Alzheimer's disease risk.

Oxidative stress plays a role in tau hyperphosphorylation and the development of neurofibrillary tangles (NFT). In Alzheimer's disease (AD) brain, accumulation of hyperphosphorylated tau in NFT is associated with the induction of heme oxygenase-1 (HO-1), a potent antioxidant that downregulates the production of tau. In a case-control study of 300 AD patients and 360 healthy controls, we examined whether the combined gene effects between HO-1 (-413, rs2071746) and tau (5' of exon 1, rs242557) polymorphisms might be responsible for susceptibility to AD.